Method for Performing a Harq Operation in a Radio Communications System, and Method and Apparatus for Allocation of Subframes

1. A method for allocating subframes in a wireless communication system that performs communication by using a radio frame including a plurality of subframes, the method comprising: receiving an uplink grant in a backhaul downlink subframe #n (n being a integer number), wherein the uplink grant comprises an offset value; transmitting uplink data based on the uplink grant in a backhaul uplink subframe #(n+4); and determining a backhaul downlink subframe in which an acknowledgement/not-acknowledgement (ACK/NACK) for the uplink data is to be received, wherein when a backhaul downlink subframe #(n+8) is a limitation subframe and the offset value indicates one subframe, the determined backhaul downlink subframe is a subframe shifted from the backhaul downlink subframe #(n+8) by the offset value and the ACK/NACK is received in the determined backhaul downlink subframe, and wherein when the backhaul downlink subframe #(n+8) is the limitation subframe and the offset value indicates more than one subframe, the determined backhaul downlink subframe is the backhaul downlink subframe #(n+8) and the backhaul downlink subframe #(n+8) is punctured, and wherein the limitation subframe is a subframe in which essential information for a relay user equipment is transmitted.

2. The method of claim 1 , wherein the radio frame is configured of ten subframes and the ten subframes sequentially have subframe indices from 0 to 9.

3. The method of claim 2 , wherein the limitation subframes are subframes having any one of the subframe indices within the radio frame corresponding to 0, 4, 5, and 9 when the wireless communication system is operated in a frequency division duplex (FDD) scheme.

4. The method of claim 2 , wherein the limitation subframes are subframes having any one of the subframe indices within the radio frame corresponding to 0, 1, 5, and 6 when the wireless communication system is operated in a time division duplex (TDD) scheme.

5. The method of claim 1 , wherein the determined subframe is an initially positioned subframe among subframes positioned after the backhaul downlink sub frame #(n+8).

6. The method of claim 1 , wherein the determined subframe is a last positioned subframe among subframes positioned before the backhaul downlink subframe #(n+8).

7. The method of claim 1 , wherein the determined subframe is a subframe temporally closest to the backhaul downlink subframe #(n+8).

8. The method of claim 1 , wherein the uplink data is transmitted through a physical uplink shared channel (PUSCH) and the ACK/NACK is received through a physical hybrid-ARQ indicator channel (PHICH).

9. The method of claim 1 , wherein the uplink grant is received through a physical downlink control channel (PDCCH).

10. The method of claim 1 , wherein the offset value indicates an interval of subframes that are to be shifted from the backhaul downlink subframe #(n+8).

11. An apparatus comprising: a radio frequency (RF) unit transmitting and receiving radio signals; and a processor connected to the RF unit, wherein the processor is configured for: receiving an uplink grant in a backhaul downlink subframe #n (n is a integer number), wherein the uplink grant comprises an offset value; transmitting uplink data based on the uplink grant in a backhaul uplink subframe #(n+4); and determining a backhaul downlink subframe in which an acknowledgement/not-acknowledgement (ACK/NACK) for the uplink data is to be received, wherein when a backhaul downlink subframe #(n+8) is a limitation subframe and the offset value indicates one subframe, the determined backhaul downlink subframe is a subframe shifted from the backhaul downlink subframe #(n+8) by the offset value and the ACK/NACK is received in the determined backhaul downlink subframe, and wherein when the backhaul downlink subframe #(n+8) is the limitation subframe and the offset value indicates more than one subframe, the determined backhaul downlink subframe is the backhaul downlink subframe #(n+8) and the backhaul downlink subframe #(n+8) is punctured, and wherein the limitation subframe is a subframe in which essential information for a relay user equipment is transmitted.

12. The apparatus of claim 11 , wherein the offset value indicates an interval of subframes that are to be shifted from the backhaul downlink subframe #(n+8).